Drones were used to search the Channel overnight after four people died when a migrant boat capsized.
Ships were also asked to post lookouts as the search continued on Thursday after 39 people were rescued in the early hours of Wednesday, with most of them understood to have been pulled from the cold water.
The Maritime and Coastguard Agency (MCA) said: “The search has continued overnight utilising a combination of aerial search assets and broadcast action requesting shipping in the area to post lookouts and report any sightings to Dover Coastguard.
“Our thoughts are with those affected by this tragic incident and with the families of those who have lost their lives.”
The Royal Navy, French navy, Coastguard and RNLI lifeboats took part in a major rescue operation off the Kent coast after they were called to a boat “in distress” at 3.05am on Wednesday.
Two casualties were taken to the William Harvey Hospital in Ashford, bosses there said.
One was later discharged but the other had died by the time they arrived, it is understood.
The Marine Accident Investigation Branch (MAIB) is carrying out a “preliminary assessment” of the incident and will decide whether an investigation will be launched once evidence has been reviewed.
A spokeswoman said: “We are in the process of gathering information about the incident as part of the process of conducting a preliminary assessment. A decision on whether an investigation will be launched will be made once the evidence has been reviewed.”
